Construction method for large-section rectangular pipe jacking to pass through river shoal and avoid obstacles

Abstract

The application discloses a construction method for a large-section rectangular pipe jacking to pass through a river shoal and to avoid obstacles, and comprises the following steps: S1, when the rectangular pipe jacking passes through the river shoal and encounters a cutter head and a screw machine, the current of the screw machine is high, and the torque of the cutter head and the screw machine increases sharply, the cause should be checked in time by means of positive and negative rotation of the cutter head and positive and negative rotation of the screw machine blade; S2, the river shoal has a small water flow, and a local excavation method can be adopted for treatment, and the river water should be diverted before local excavation; S3, a shovel is adopted to excavate and clean the soil, rock filling and the like in the soil range of the river bed in front of the pipe jacking machine, and the excavation depth is the soil depth from the top of the pipe jacking machine to the bottom of the river bed; S4, according to the cutter head and the screw machine stuck situation, the pipe jacking machine is smoothly pushed to the other side of the river by adopting the single screw machine to unload or not to unload; and S5, after the pipe jacking machine smoothly passes through the river, the treatment of the boulders at the cutter head or the screw machine is carried out, at this time, the conditions for opening the warehouse for treatment are much better than those at the bottom of the river, and the construction safety is more effectively guaranteed. The method is safe and efficient, and construction cost is saved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of pipe jacking construction technology, in particular to a large-section rectangular pipe jacking construction method for passing through river shoal. BACKGROUND

[0002] With the large-scale development and utilization of urban underground space, rectangular pipe jacking technology has been gradually applied to urban underground passages, comprehensive pipe galleries and other projects. Compared with the traditional open-cut method, the rectangular pipe jacking technology has the advantages of small impact on the surrounding environment, rapid construction, high automation degree and low cost. However, due to the shape of the rectangular pipe jacking excavation surface, the cutter head cannot cut the full section, and there will be an excavation blind area in the four corners of the rectangular section and the middle area between adjacent cutter heads. When the rectangular pipe jacking passes through the river shoal and other river bottom space abnormal strata, there may be boulders such as rock filling and riprap that cause the cutter head of the pipe jacking machine or the screw to be stuck and unable to normally jacking.

[0003] Currently, there are two main ways to deal with the problem of the cutter head of the pipe jacking machine or the screw being stuck. The first way is to open the bin, that is, to enter the soil pressure bin through the reserved hole on the chest plate of the pipe jacking machine to break the boulders. The second way is to open a skylight, that is, to excavate above the machine head until the entire machine head is completely exposed, and then deal with the boulders. Both of these two ways have some drawbacks. The former has high construction risk and requires the stratum to have certain self-stability. It is not advisable to open the bin recklessly under the condition of rich water in the river bottom. The latter requires a large amount of excavated earth, has a long construction period and high cost, and there is a certain risk in deep foundation pit excavation. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a large-section rectangular pipe jacking construction method for passing through river shoal to achieve the purposes of safety and efficiency, and low construction cost.

[0005] In order to solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0006] The large-section rectangular pipe jacking construction method for passing through river shoal includes the following steps:

[0007] S1. When the rectangular pipe jacking passes through the river shoal and the current of the cutter head and the screw machine is high, and the torque of the cutter head and the screw machine increases sharply, the cause should be investigated in time by means of forward and reverse rotation of the cutter head and forward and reverse rotation of the screw machine blade;

[0008] S2. When the water flow of the river shoal is small, the local excavation method can be used for treatment. Before local excavation, the river water should be diverted. According to the position of the pipe jacking machine head trapped by measurement and exploration, earth and stone dams are built on the upstream, downstream and middle of the river to divert the river water to the ground surface behind the pipe jacking machine. The river water flow is obviously different at different times, and the river water diversion work should be carried out at the time when the river water flow is the smallest.

[0009] S3. Adopting excavator to excavate and clean the soil, rock filling and so on in the range of the earth covering of the river bed in front of the pipe jacking machine, the excavation depth is the earth covering depth from the top of the pipe jacking machine to the bottom of the river bed;

[0010] S4. According to the situation of the cutter head and screw machine being stuck, the pipe jacking machine is smoothly pushed to the opposite bank of the river by the way of unilateral screw machine unearthing or not unearthing;

[0011] S5. After the pipe jacking machine smoothly passes through the river, the treatment of the boulders at the cutter head or screw machine is carried out, at this time, the conditions of opening the warehouse are much better than at the bottom of the river, and the construction safety is more effectively guaranteed.

[0012] Among them,

[0013] In the step S1, when it is determined that the cutter head and screw machine are stuck by large boulders, the jacking should be stopped immediately; after the pipe jacking is stopped, the excavation surface should be taken pressure maintaining measures, and the monitoring work of the surface deformation in front of the cutter head should be done well; when the surface settlement is out of limit, the concentrated mud can be injected through the reserved grouting hole on the chest plate of the pipe jacking machine to the front of the cutter head, which plays a certain lifting role on the surface in front of the pipe jacking machine head; at the same time, in order to prevent the pipe jacking machine cutter head from being adhered by the soil due to too long stop time, the cutter head should be appropriately rotated at intervals.

[0014] In the step S2, in order to prevent the river water after diversion from entering the local excavation area through the soil layer gap, the following measures can be taken: ① waterproof cloth can be laid on the bottom of the diversion area, the water surface of the earth-rock dam and other areas; ② large diameter corrugated pipe is buried in the diversion area, and the corrugated pipe and the earth-rock dam are filled with clay to make the river water after diversion flow through the corrugated pipe as much as possible.

[0015] In the step S3, the river bed surface above the machine head should also be selected to be carried out at the time when the river flow is the smallest.

[0016] In the step S3, after the surface above the machine head is exposed, the whole pipe jacking machine shell is in a pressure relief state, and the attitude of the machine head is difficult to control when re-jacking, therefore, according to the actual prediction of the boulder stuck position, the excavation depth, the normal rotation side of the cutter head or the normal unearthing side of the screw machine should be reserved 1 / 3-1 / 2 thickness of the covering layer, a certain counter pressure is formed to ensure the jacking attitude.

[0017] In the step S4, when the pipe jacking is jacked under the condition of partial unearthing or no unearthing, the problems of excessive jacking force, surface uplift in front, pipe jacking machine rotation or upward may occur, and strict monitoring and control should be done during construction.

[0018] In the step S4, the case of excessive jacking force; the monitoring of the stress and displacement of the backrest and pipe joint should be done well, if abnormal situation is found, the construction should be stopped immediately to investigate the reason; at the same time, the friction reducing grouting behind the pipe jacking wall should be strengthened to reduce the pipe side resistance to the minimum.

[0019] In the step S4, the ground in front of the pipe jacking machine is raised: because the river water has been diverted in advance and the ground in front of the machine head has been partially excavated, the ground raising has little influence on the pipe jacking construction and the surrounding environment, and when the ground is raised, a long-arm excavator can be used to assist in the earth removal.

[0020] In the step S4, the attitude of the pipe jacking machine is out of limit: during the pipe jacking, the roll angle and the pitch angle of the machine head should be monitored; when the roll angle of the machine head is out of limit, the earth removal speed should be slowed down, and the deviation can be corrected by reversing the rotating cutter head; when the pitch angle of the machine head is out of limit, the deviation can be corrected by using the active hinge cylinder of the machine head, and the center of gravity of the main jacking cylinder can also be adjusted to assist in the deviation correction.

[0021] Compared with the prior art, the present application has the following advantages:

[0022] The large-section rectangular pipe jacking under-crossing river shoal obstacle escape construction method is reasonable in design, and through the river water local diversion, the riverbed uncovering above the machine head, the pipe jacking partial earth removal and other construction steps, the rectangular pipe jacking machine successfully crosses the complex and variable riverbed bottom and reaches the area with the condition for opening the warehouse, effectively reduces the great risk brought by the riverbed opening treatment or the large excavation of the riverbed, shortens the pipe jacking downtime, saves the construction period and reduces the construction cost. BRIEF DESCRIPTION OF DRAWINGS

[0023] The content expressed by each figure in the present specification and the marks in the figures are briefly described as follows:

[0024] Figure 1 It is a construction process schematic diagram of the construction method of the present application.

[0025] Figure 2 It is a construction method schematic diagram of the present application.

[0026] Figure 3 It is Figure 2 A partial enlarged schematic diagram.

[0027] Figure 4 It is a top view schematic diagram of the construction method of the present application.

[0028] In the figure:

[0029] 1. Starting well, 2. Pipe section, 3. Pipe jacking machine, 4. Excavator. DETAILED DESCRIPTION

[0030] The specific embodiments of the present application are further described in detail below by comparing the embodiments with the description of the drawings.

[0031] As Figures 1 to 4As shown, the large-section rectangular pipe jacking under the river shoal barrier construction method includes the following construction steps:

[0032] S1. When the rectangular pipe jacking under the river shoal encounters a cutterhead and the current of the screw machine is high, and the torque of the cutterhead and the screw machine increases sharply, the cause should be investigated in time by means of forward and reverse rotation of the cutterhead and the screw machine blade. When it is determined that the cutterhead and the screw machine are stuck by large boulders, the jacking should be stopped immediately. After the starting well 1 and the pipe jacking machine 3 are stopped, the excavation face should be pressurized, and the monitoring of the deformation of the ground surface in front of the cutterhead should be done. When the ground surface settlement exceeds the limit, thick mud can be injected in front of the cutterhead through the reserved grouting hole on the chest plate of the pipe jacking machine to lift the ground surface in front of the pipe jacking machine head. At the same time, in order to prevent the pipe jacking machine cutterhead from being adhered by the soil due to long downtime, the cutterhead should be rotated appropriately at intervals.

[0033] S2. The river shoal has small water flow, which can be treated by local excavation. Before local excavation, the river water should be diverted. According to the stuck position of the pipe jacking machine head measured and explored, earth and stone dams are built on the upstream, downstream and middle of the river to divert the river water to the ground surface behind the pipe jacking machine, as shown in Figure 4 . The river water flow varies significantly at different times, and the river water diversion work should be carried out at the time when the river water flow is the smallest. It needs to be further explained that, in order to prevent the river water after diversion from entering the local excavation area through the soil layer gap, the following measures can be taken: ① waterproof cloth can be laid on the bottom of the diversion area and the water-facing surface of the earth and stone dam; ② large-diameter corrugated pipes are buried in the diversion area, and the corrugated pipes and the earth and stone dam are filled with clay to make the river water after diversion flow through the corrugated pipes as much as possible.

[0034] S3. The long-arm excavator 4 is used to excavate and clean the soil and rock filling in the range of the earth cover in front of the pipe jacking machine, and the excavation depth is the earth cover depth from the top of the pipe jacking machine to the river bed, as shown in Figure 2 and 3 . Since the excavation amount is relatively small, and the long-arm excavator is located on the river bank, no personnel are needed in the excavation area, so no special support is needed in the excavation area. The river bed above the machine head should also be selected at the time when the river water flow is the smallest. It needs to be further explained that, after the ground surface above the machine head is exposed, the entire pipe jacking machine shell is in a pressure relief state, and the attitude of the machine head is difficult to control when jacking again. Therefore, according to the actual prediction of the boulder stuck position, the excavation depth should be controlled, and the normal rotation side of the cutterhead or the normal earth discharge side of the screw machine should be reserved 1 / 3-1 / 2 thickness of the cover layer to form a certain counterpressure and ensure the jacking attitude.

[0035] S4. According to the cutter head and screw machine stuck situation, the unilateral screw machine is used to unearth or not to unearth, and the pipe jacking machine is smoothly pushed to the other side of the river. It is worth noting that when the pipe jacking is jacked under partial unearthing or no unearthing, problems such as excessive jacking force, ground uplift in front, pipe jacking machine rotation or upward inclination may occur, and strict monitoring and control should be done during construction:

[0036] ① Excessive jacking force. The stress and displacement of the backrest and pipe section 2 should be monitored, and if abnormal conditions are found, construction should be stopped immediately to investigate the cause; at the same time, pipe wall back friction reduction grouting should be strengthened to minimize pipe side resistance.

[0037] ② Ground uplift in front of the pipe jacking. Because the river water has been diverted in advance and the ground in front of the machine head has been partially excavated, the ground uplift will not have too much impact on the jacking construction and the surrounding environment. When the ground uplift occurs, a long-arm excavator can be used to assist in unearthing.

[0038] ③ Pipe jacking machine attitude out of limits. During jacking, the roll angle and pitch angle of the machine head should be monitored. When the roll angle of the pipe jacking machine head exceeds the limit, the unearthing speed should be slowed down, and the cutter head can be rotated in the opposite direction to correct the deviation; when the pitch angle of the pipe jacking machine head exceeds the limit, the active hinge cylinder of the machine head can be used to correct the deviation, and the center of gravity of the main jacking cylinder can also be adjusted to achieve the effect of auxiliary deviation correction.

[0039] S5. After the pipe jacking machine successfully passes through the river, the treatment of boulders at the cutter head or screw machine is carried out. At this time, the conditions for opening the warehouse for treatment will be much better than at the bottom of the river, and the safety of construction is more effectively guaranteed.

[0040] The present application passes through the river bottom with complex changes by local diversion of river water, uncovering of the riverbed above the machine head, and partial unearthing of the pipe jacking, so that the rectangular pipe jacking machine successfully passes through the complex riverbed bottom and reaches the area with conditions for opening the warehouse for treatment, effectively reducing the risk of river bottom opening treatment or large excavation of the river bottom, shortening the pipe jacking downtime, saving the construction period and saving the construction cost.

[0041] The above describes the present application in conjunction with the drawings, and it is obvious that the specific implementation of the present application is not limited to the above manner. Any non-essential improvement or direct application of the concept and technical solution of the present application to other occasions without improvement is within the protection scope of the present application.

Claims

1. A method for constructing a large-section rectangular pipe jacking tunnel under a shallow riverbed and overcoming obstacles, characterized in that: The construction method includes the following steps: S1. When a rectangular jacking pipe encounters a situation where the current of the cutter head and screw conveyor is high and the torque of the cutter head and screw conveyor increases sharply when passing under a shallow river, the cause should be investigated in a timely manner by reversing the cutter head and screw conveyor blades. S2. The river shallows have a small water flow, so a partial excavation method will be used for treatment. Before carrying out partial excavation, the river water should be diverted. Based on the location of the pipe jacking machine head that is trapped, as determined by measurement and exploration, earth and rock dams will be built in the upstream, downstream and middle parts of the river to divert the river water to the ground surface behind the pipe jacking machine. The river water flow varies significantly at different times, so the diversion work should be carried out during the period of lowest river flow. S3. Use an excavator to excavate and clear the soil and rocks within the cover area of ​​the riverbed in front of the pipe jacking machine. The excavation depth is the cover depth from the top of the pipe jacking machine to the bottom of the riverbed. S4. Depending on whether the cutterhead or screw conveyor is stuck, the pipe jacking machine can be smoothly advanced to the other side of the river by using either single-sided screw conveyor for soil removal or non-soil removal. S5. After the pipe jacking machine has successfully crossed the river, the isolated rocks at the cutterhead or screw conveyor should be dealt with. At this time, the conditions for opening the chamber will be much better than at the bottom of the river, and the construction safety will be more effectively guaranteed.

2. The construction method for large-section rectangular pipe jacking under river shallows and overcoming obstacles as described in claim 1, characterized in that: In step S1, if it is determined that the cutter head or screw is jammed by a large boulder, the jacking should be stopped immediately. After the pipe jacking machine is shut down, pressure maintenance measures should be taken at the excavation face, and the deformation of the ground surface in front of the cutterhead should be monitored. When the ground settlement exceeds the limit, thick mud should be injected into the front of the cutterhead through the reserved grouting holes on the breast plate of the pipe jacking machine to lift the ground surface in front of the pipe jacking machine head. At the same time, in order to prevent the cutterhead of the pipe jacking machine from being stuck to the soil due to the long shutdown time, the cutterhead should be rotated appropriately every once in a while.

3. The construction method for large-section rectangular pipe jacking under river shallows and overcoming obstacles as described in claim 1, characterized in that: In step S2, to prevent the diverted river water from entering the local excavation area through the gaps in the soil, the following measures are taken: ① Waterproof tarpaulin is laid at the bottom of the diversion area and on the water-facing side of the earth-rock dam; ② A large-diameter corrugated pipe is buried in the diversion area, and the space between the corrugated pipe and the earth-rock dam is filled with clay so that the diverted river water flows through the corrugated pipe as much as possible.

4. The construction method for large-section rectangular pipe jacking under river shallows and overcoming obstacles as described in claim 1, characterized in that: In step S3, the riverbed clearing work above the machine head should also be carried out during the period when the river flow is at its lowest.

5. The construction method for large-section rectangular pipe jacking under river shallows and overcoming obstacles as described in claim 1, characterized in that: In step S3, after the ground surface above the machine head is exposed, the entire casing of the pipe jacking machine is in a depressurized state. When jacking again, the attitude of the machine head is difficult to control. Therefore, the excavation depth should be controlled according to the actual predicted position of the boulder jamming. A cover layer of 1 / 3 to 1 / 2 thickness should be reserved on the side where the cutterhead rotates normally or the side where the screw excavator discharges soil normally to form a certain back pressure and ensure the jacking attitude.

6. The construction method for large-section rectangular pipe jacking under river shallows and overcoming obstacles as described in claim 1, characterized in that: In step S4, when the pipe jacking is carried out with or without soil removal, problems such as excessive jacking force, ground heave in front, rotation or upward tilting of the pipe jacking machine may occur. Close monitoring and control should be carried out during the construction process.

7. The construction method for large-section rectangular pipe jacking under river shallows and overcoming obstacles as described in claim 6, characterized in that: In step S4, if the jacking force is too high, the stress and displacement of the backrest and pipe section should be monitored. If any abnormality is found, construction should be stopped immediately and the cause investigated. At the same time, the friction-reducing grouting behind the jacking pipe wall should be strengthened to minimize the pipe side resistance.

8. The construction method for large-section rectangular pipe jacking under river shallows and overcoming obstacles as described in claim 6, characterized in that: In step S4, the ground surface in front of the pipe jacking machine rises: Since the river water has been diverted in advance and the ground surface in front of the machine head has been partially excavated, the ground surface rise will not have a significant impact on the jacking construction and the surrounding environment. When the ground surface rises, a long-arm excavator is used to assist in soil removal.

9. The construction method for large-section rectangular pipe jacking under river shallows and overcoming obstacles as described in claim 6, characterized in that: In step S4, the attitude of the pipe jacking machine exceeds the limit: During the jacking process, the roll angle and pitch angle of the machine head should be monitored; when the roll angle of the pipe jacking machine head exceeds the limit, the excavation speed should be slowed down, and the reverse rotation of the cutterhead should be used to correct the deviation; when the pitch angle of the pipe jacking machine head exceeds the limit, the active articulation cylinder of the machine head should be used to correct the deviation, and the center of the resultant force of the main jacking cylinder can also be adjusted to achieve an auxiliary correction effect.

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